Throat plate for sewing machines



Nov. 8, 1938. F. EBERT 2,136,288

THROAT PLATE FOR SEWING MACHINES Filed Jan. 25, 1955 5 Sheets-Sheet 1 f/orrrey.

NOV. 8, 1938. EBERT 2,136,288

THROAT PLATE FOR SEWING MACHINES Filed Jan. 25, 1935 5 Sheets-Sheet 2 Afformey,

Nov. 8, 1938. F. EB ERT 2,136,288

THROAT PLATE FOR SEWING MACHINES Filed Jan. 25, 1935 5 Sheets-Sheet 3 HI me. 1mm

Nov. 8, 1938.

F. EBERT THROAT PLATE FOR SEWING MACHINES 5 Sheets- Sheet 4 Filed Jan. 23, 1 955 AWo/wey.

Nov. s, 1938. F. EBERT 2,136,288

THROAT PLATE FOR SEWING MACHINES Filed Jan. 25, 1935 5.Sheets-She et 5 Patented Nov. 8, 1938 4 UNITED STATES PATENT ()FFIQE THROAT PLATE FOR SEWING MACHINES pany of Germany Application January 23, 1935, Serial No. 3,168 In Germany January 29, 1934 3 Claims.

The present invention relates to needle plates or throat-plates for sewing machines.

The primary object of the invention is to provide a throat-plate for sewing machines which 5' will satisfactorily guide the fabric portions to be united to the needles of the sewing machine whereby a seam having the combined fastening and seam covering stitchings may be effected. In accomplishing this latter, I provide a throatplate with a resilient hem fold guide with a guide. tongue or portion and the latter having the necessary channel or opening therein to accommodate the usual upper movable knife of the trimming mechanism of the sewing machine. 15 Compared with known devices of this kind, the present device has the essential advantage in that the guide portion with its lateral edge serves as a stop and does not extend above the upperface of the throat-plate. The guide por- 20 tion is, moreover, resiliently arranged, so that, if cross seams occur, the vertical space between the right hand side of the throat-plate and the hem fold guide, provided at the left hand side, may be enlarged.

. The hem fold guide may be adjusted according to the desired width of trimming and the thickness of the material to be handled. At two points the resilient hem fold guide is reduced in cross section or weakened, so that the long shank alone as well as together-with the resilient guide tongue may yield upon pressure being applied thereto.

To prevent the formation of bunches and in order to tension the scam, the tongue portion for the cover seam may be arranged in an elevated position with regard to the remaining part of the throat-plate.

A further feature of the invention consists in that the correct width for piercing may always 40' be maintained. For this purpose an adjustable guide member is provided at the right hand side .of the throat-plate by means of which the fabric is guided in such a manner that it will always be correctly pierced. The guide member may also 45 be resiliently pivoted to the throat-plate. This guide member on the throat-plate provides the further advantage that a special stop at the presser foot may be disposed with thereby materially facilitating the withdrawing of the fabric from the cylinder.

In a modification of the throat-plate according to the invention in which the stitch hole for the middle needle is arranged in front, a projection, extending until in front of the stitch holes for 55 the needles producing the cover seam, is laterally provided at the left hand guide member which also is fixed to the throat-plate. By this lateral projection the ridge of the seam is vertically folded so that it may be covered in this position.

In the accompanying drawings, forming part of the specification, some constructions of throatplates according to the invention are shown by way of example.

In these drawings:

Fig. 1 is a front elevation of a throat-plate, Fig. 2 shows a side view, looking from the right of Fig, 1,

Fig. 3 is a side view, looking from the left of Fig. 1,

Fig. 4 shows a plan view, Fig. 4a is .a section on the line IVa;-IVa of Fig. 4,

Fig. 5 is a section on the line VV of Fig. 4,

Fig. 6 is a plan view, corresponding to Fig. 4, showing a modification having aligned. stitch holes.

Fig. 6a is a section on the line VIaVIa of Fig. 6,

Fig. '7 is a front elevation, showing a further modification of the throat-plate according to the invention,

Fig. 8 is a side view, looking from the right of Fig. 7,

Fig. 9 is a side view, looking from the left of Fig. 7,

Fig. 10 shows a plan view,

Fig. 10a is a section on the line XaXa of Fig. 10.

Fig. 11 is a section on the line XIXI of Fig. 10,

Fig. 12 is a front elevation of a third modification of the throat-plate according to the invention,

Fig. 13 is a side view, looking from the right of Fig. 12,

Fig. 14 is a side view, looking from the left of Fig. 12,

Fig. 15 shows a plan view,

Fig; 16 is a section on the line XVI-XVI'of Fig. 15,

Fig. 17 is a section on the line XVII-XVII of Fig. 15,

Fig, 18 shows a detail plan view of the guide member,

Fig. 19 is a section on the line XIX-XIX of, Fig. 18,

Fig. 20 is a front elevation of a still further modification of the throat-plate according to the invention,

Fig. 21 is a side view, looking from the right of Fig, 20,

Fig. 22 is a side view, looking from the left Fig. 20,

Fig. 23 is a plan view,

Fig. 23a is a sectional view taken on line XX[IIa--XXIIIa of Fig. 23 with the addition of the fabric portions in their relative position.

Fig. 23?) is a sectional view taken on line XXIIIbXXIIIb of Fig. 23 with the addition of the fabric portions in their relative position.

Fig. 230 is a sectional view taken on line XXIIIc-XXIIIC of Fig. 23 with the addition of the fabric portions in their relative position.

Fig. 23d is a sectional view taken on line XXIIIdXXIIId of Fig. 23 with the addition of the fabric portions in their relative position.

Fig. 24 is a section on the line XXIV-XXIV of Fig. 23,

Fig. 25 is a section on the line XXV-XXV of Fig. 23, showing the connection of the throatplate to the support,

Fig. 26 is a detail side view of the guide member and Fig. 27 shows a plan view of the guide member.

Figures l-5 and 7-11 show constructions of a throat-plate for sewing machines on which the fastening or joining seam and the cover seam are produced separately, i. e., a throat-plate in which one of the stitch holes is arranged in front of the other stitch holes, and Fig. 6 shows a plan view, corresponding to that of Figures 4 and 10, of a throat-plate having all three stitch holes arranged in alignment or in the same direction, 1. e., a throat-plate for sewing machines on which the fastening or joining seam and the cover seam are made simultaneously.

The construction shown in Figures 1-5, inclusive, is particularly adapted for thin fabrics, and the throat-plate l in this case is provided with a special resilient hem fold guide 2, having a guide tongue 3 with a slot lthrough which may operate the upper knife (not shown) of a trimming mechanism, particularly of the kind disclosed in Patent No. 2,044,275 of June 16, 1936.

The body portion of the throat-plate con sists of a laterally extending rear end portion A preferably of an arcuate configuration in order that it may be applied to the outer end of the usual carrier arm of the sewing machine and has the openings B formed therein for the reception of screws or similar means for fastening the throat-plate to the carrier arm of the sewing machine. Formed with and extending from one edge of the rear end portion A are a pair of spaced parallel arms C and D and the upper faces of these arms lie substantially flush with that of the rear end portion A. The outer or free end of the arm D is provided with an openingE for the reception of a screw or similar means required for attaching the same to the carrier arm of the sewing machine. The hem fold guide 2 consists of a plate having a relatively long shank 2 which is seated within a recess formed within the upper face of the arm C whereby the upper face of this guide plate will lie flush with that of the body portion of the throat-plate. Formed with the outer end of the shank 2 and ext-ending at one side thereof is a guide tongue 3. This guide tongue being so suspended within the space provided between the arms C and D establishes between its outer longitudinal edge and the sloping edge or face F of the arm D a channelway through which is fed the hem portions of the pieces of fabric to be united. According to the desired width of trimming and to the thickness of the material to be handled, the guide part 2 may be adjusted in a recess 5 of the throat-plate I, whereupon it may be fixed to the latter by means of a screw 6. The cross section of the fold guide part 2 is reduced at two points I and 8, whereby not only resiliency of the long shank 2, but also of the guide tongue 3, provided with the slot 4 for the passage of the upper knife (not shown) of the trimming mechanism, is obtained. In this way, fabrics having cross seams may conveniently be passed through the machine, without such cross seams forming an obstacle. An opening H is formed within the arm D and a similar opening I is formed between the arms C and D, both of which accommodate the usual feed dogs of the sewing machine.

An inclined guide l6, formed with the arm D has extending therethrough the stitch hole 9 for the needle of the trimming seam, has the effect, that the seam ridge, on the short way to the stitch holes I I and I2 for the needles of the cover seam, is folded and therefore during covering lies fiat.

By this method it is, however, also possible to produce a single seam and for this purpose, the stitch hole for the needle connecting or joining the two fabric edges is arranged as the middle hole of three or more parallel stitch holes I4, provided in one plane or in alignment with the other stitch holes (see Fig, 6). The two pieces or webs of fabric are thereby folded in exactly the same manner. By means of the inclined guide l3 also provided in this case, the two pieces of the fabric are folded flat in front of the three stitch holes i l, arranged in a single plane or in alignment, and are, therefore, sewn together by the three needles, not shown in the drawings, working in these three stitch holes.

The construction shown in Figures 7-11, inelusive, is particularly adapted for thicker fabrics and also has all the advantages mentioned above. The substantial difference between this modification and that already described consists in this, that the tongue portion 55 for the cover seam is arranged in elevated position with regard to the remaining part of the throat-plate l, whereby the effect of the inclined guide 16, provided for folding the seam ridge or the two parts of the fabric respectively, is particularly enhanced. The advantage obtained by this construction is, that the seam may be stretched or tensioned, whereby the formation of bunches is prevented.

The arrangements illustrated are suitable for sewing machines provided with an overhanging arm and adapted for feeding in the upward direction of the arm. The advantages obtained with such machines may, however, also be obtained with sewing machines provided with an overhanging arm adapted for feeding in the downward direction of the arm or across the arm as well as for flat bed sewing machines.

According to the modification shown in Figures 12-19, inclusive, a recess 56 is provided in the upper face of the outer extremity of the arm D of the throat-plate l in which a guide member l1 is arranged which may be fixed by means of a screw I8. The guide member I! is adjustably mounted, so that its guide edge l9 may be brought into its correct position according to the material to be handled. As a result, correct piercing of the needles through the fabric is always warranted.

The guide member H is provided with an opening 26 which registers with the opening E of the arm D to accommodate an attaching screw, whereas the arm C and the hem fold guide 2 may have an aligning opening J' therein through which may extend a screw or other suitable means for attaching'the same to the carrier arm of the sewing machine.

According to the modification shown in Figures 20-27, inclusive, the guidemember I1 is resiliently and pivotally connected to the throat-plate I. A. screw 2 I. serves; as pivot for. the guide member I1 and simultaneously for attaching the outer end of' the arm D of the throat-plate I and the 1 II, bears against the throat-plate I and serves to limit the movement of the guide member I I in one direction against the action of the spring 26 and to allow an exact adjustment of the desired width of piercing. Fig, 23d shows in cross section the operation of the adjusting screw 28 whereby member I! can 'be adjusted relative to its supporting arm. As shown, adjusting screw 28 is mounted through a portion of the guide member I1 and by rotating said adjusting screw 28, it may be caused to bear against the arm of the throat-plate I. By this means, the pivotal movement of guide member I! can be adjusted in order that resilient spring 26 cannot move the end portion of the guide member I! in a horizontal position a distance greater than the said adjusting screw 28 will permit. A set screw 29 presses against the spring 26, so that the tension of the latter and thereby the pressure against the guide member I! may be controlled. The resilient arrangement has the advantage, that the guide edge I9 of the guide member I! yields as soon as a cross seam passes. A stop 30, fixed to the left hand side of the throat-plate I, carries a lateral projection 3| which extends until in front of the stitch holes 32 for the needles producing the cover seam, and which serves to vertically fold the ridge of the seam, so that the latter may be covered in this position. In operation, the fabric portions are fed into the sewing machine in such a manner that the left hand fabric portion is placed in an acute angle along a hem fold guide 30 and the right hand fabric portion in an obtuse angle along the guide member I I. In this angular position, both fabric portions are trimmed, whereupon, they are fed towards the needle joining them together. Should cross seams occur, that is to say, should by the thickening of the fabric the passage become too small, then the guide edge I9 may resiliently move upwardly at two points and the guide member I! may resiliently swing towards the right, thereby enlarging the passage. From the needle joining the two fabric portions the latter move, after the seam ridge has been placed vertically by the projection 3| to the covering needles. According to the nature of the fabric to be sewn, the hem fold guide 30 may be adjusted in a slot and fixed in the adjusted position by means of the screw 6. This adjustment serves the purpose of controlling the width at which piercing of the fabric is effected. The right hand portion of stop I! is resiliently mounted so as to yield on the occurrence of cross seams. The spring pressure may be regulated by means of the screw 29. A further screw 28 bearing against the throat-plate serves to limit the swinging movement of the stop I1, thus maintaining at all times a certain width of passage.

Fig; 23a shows .in'cross section the fabrics to be sewn together and the coacting parts in their relativepositions before the knives a and b have cut the edges of the fabric portion 0 and d. Figure 23b is a cross sectional view of the step following that shown in 23a and discloses the joining needle e operating in stitch 'hole-9, in frontv of the two covering needles f which pass through the stitch holes 32. In this secondfstep, the edges of the fabric portions 0 and'dare already cut and bent against one anotherto obtain the position required for joining the two fabric portions. Fig. .230 discloses the third step wherein the joining seam g has been produced and the edges of the fabric portions 1: and d lie flat in the position required for covering. It can be seen from the foregoing steps that the lefthand piece 0 of the fabric is, when fed into the machine, bent at an acute angle which progressively decreases until the cover needles. ,f are reached. The righthand piece d of the fabric is fed into the machine at an obtuse angle which progressively increases until the said covering needles 1 are reached. The joining needle e, uniting the two pieces 0 and d of the fabric and thereby forming the joining seam g; operates in front of the two covering needles I.

As shown in Fig. 23, in operation a knife 22 is adjustably mounted upon the arm of the throat-plate I which supports guide member II. This knife 22 is provided with an elongated slot 35 whereby the usual screw passing through the arm of the throat-plate I passes also through the said slot and by means of the tightening action of the usual screw, the knife 22 can be moved in a horizontal direction whereby the cutting edge of the knife may be adjustable relative to the usual cutting blade a. Knife 22 is so shaped, as is shown in Fig. 23, to permit it to be readily mounted under the arm of the throat-plate I without interfering with the movement of members relative to said throat-plate I and yet the cutting edge of blade 22 can readily coact with knife a, whereby cloth 0 and d may be readily cut by the scissors-like action of the knives a and 22.

Figures 12-19, inclusive, show a modification of a throat-plate for a sewing machine, having the three stitch holes for the needles arranged in a single plane or in alignment, while Figures 20-30, inclusive, illustrate a construction of the throat-plate for a sewing machine in which the stitch hole for the middle needle is arranged in front of the two lateral stitch holes. Of course, the one modification as wellas the other may be used for both positions of the needles.

The invention is, moreover, not intended to be limited to the illustrated modifications of the throat-plate for sewing machines adapted for feeding the fabric in the upward direction of the arm, but may also be employed in connection with any kind of throat-plates.

What I claim is:

1. A throat-plate for sewing machines comprising a body portion, a pair of arms formed with and extending from said body portion, said arms being arranged parallel to one another to provide a feed channel therebetween and each having their upper faces lying in a plane flush with that of the upper face of said body portion, a hem fold guide member flexibly connected to one of said arms, an adjustable guide member connected to the other of said arms and the last mentioned arm having needle openings arranged therein.

2. A throat-plate mechanism for sewing mav chines comprising an arcuate body portion capable of being fixedly connected to the carrier arm of the sewing machine, a pair of spaced arms formed with said arcuate portion providing a guide channel therebetween, a hem fold guide member resiliently supported upon one of said arms, the upper faces of said hem fold guide members and arms lying in a plane flush with that of the upper face of said arcuate body portion, said throat-plate having needle openings formed therein and a tongue portion formed with the throat-plate about said needle openings ex tending in an elevated position above that of the upper face of the throat-plate.

3. A throat-plate for sewing machines comprising a body portion, a pair of arms formed with and extending from said body portion, said arms being arranged parallel to one another to provide a feed channel therebetween and each having their upper faces lying in a plane flush with that of the upper face of said body portion, a hem fold guide member flexibly connected to one of said arms, a guide member pivotally and resiliently mounted upon the other of said arms in such a manner that said guide member may yield in a horizontal direction away from said feed channel and the last mentioned arm having needle openings arranged therein.

FRITZ EBERT. 

